JP2012192306A - System for removing and treating sea bottom sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for removing and treating sea bottom sludge that has steps of efficiently treating a massive amount of dredged sludge until final disposal.SOLUTION: The system includes: a treatment tank 3 for receiving high-water content dredged sand containing muddy organic matters a groove-like wastewater drain 4 formed in the bottom 17 of the treatment tank 3; a filtration sheet 10 attached to cover an opening end of the wastewater drain 4; a waterproof sheet 11 disposed to cover the bottom 17 other than the wastewater drain 4; and sand 12 layered on the filtration sheet 10 and the waterproof sheet 11.

Description

  The present invention relates to a seabed sludge removal treatment system. Specifically, the present invention relates to a seabed sludge removal treatment system that efficiently removes organic sedimentation surface mud from the sea area and the seabed, and further treats harmful substances and performs final disposal.

In addition, the seabed sludge referred to here has a slight content of environmental hormones such as organic tin, high water content, light specific gravity (1.1 t / m ³ to 1.2 t / m ³ ), sulfide, organic matter, Surface mud that covers the seabed with a high content of total nitrogen and total organic carbon, and mud and floating mud formed from fine particles that are difficult to settle on the seabed. These react with sulfate-reducing bacteria that exist on land and in water to generate sulfur gas, causing anoxic conditions, resulting in drastic reduction of healthy benthic organisms and proliferation of anaerobic benthic organisms. By interfering with the ability of organisms to digest organic matter that always settles, the generation of sulfur gas is further repeated, and a vicious cycle is formed in which the growth of healthy animal and plant plactones is inhibited.

In recent years, there has been a demand for removal treatment of harmful seabed sludge accumulated on the seabed of marine products such as harbors, fishing ports and farms.
At present, there is a so-called sand-capping method that covers the surface of the seabed sludge with healthy sand. However, if there is organic residue on the bottom of the sand-covered sand, sulfur dioxide gas is generated by the action of sulfate-reducing bacteria. The gas fills the coated sand and then reaches the surface. As a result, the anaerobic organisms move from the sand-covered bottom surface to the surface layer, surpassing the surface healthy organisms and become unhealthy again.

Here, for example, a method described in Patent Document 1 is known as a method of landing seabed sludge by dredging or suction and performing purification treatment on land.
Specifically, as shown in FIG. 6, at least a first reaction tank 101 for filling sludge containing seabed sludge and adding vitamins to perform a decomposition reaction, and oxygen-free gas in the sludge. An aeration tube 102 for aeration, a supernatant liquid of sludge, a liquid feeding means 103 for extracting a supernatant liquid containing an organic substance produced by a sludge decomposition reaction, and supplying the supernatant liquid, A reaction tank for performing an acid decomposition reaction, the second reaction tank 104 containing microorganisms having organic acid decomposability, and means for removing gas generated by the decomposition of the organic acid from the second reaction tank 104; 2. Description of the Related Art A sludge treatment apparatus having a means for discharging discharged liquid after decomposing an organic acid is known.

JP 2003-47996 A

  However, it is necessary to treat dredged sludge continuously and in large quantities on the beach or on the ship. However, the sludge treatment apparatus described in Patent Document 1 has a processing capacity for carrying out sludge treatment in two reaction tanks. There is a limit.

  In addition, sludge to be drowned contains a lot of earth and sand and floc-forming substances, and there is a problem in treating such high-water-containing sludge and disposing it in the ocean.

  Further, the seabed sludge may be treated as general waste when it does not contain environmental hormones such as organotin and harmful substances such as heavy metals, or when the amount of components does not affect the biological environment. Therefore, as in the sludge treatment apparatus described in Patent Document 1, it is very inefficient to perform the treatment by decomposing and treating the organic matter in the reaction tank without investigating the sludge components in advance.

  The present invention was devised in view of the above points, and provides a submarine sludge removal treatment system that can realize efficient and large-scale processing up to final disposal of trapped sludge. It is intended to provide.

  In order to achieve the above object, a seabed sludge removal treatment system according to the present invention is formed on a bottom surface of a treatment tank into which dredged sand with a high water content containing muddy water is put. A groove-shaped drainage drain, a filtration sheet covered at the open end of the drainage drain, a waterproof sheet covered on the bottom surface other than the drainage drain, and laminated on the filtration sheet and the waterproof sheet. With sand.

  Here, dredged dredged sand containing organic matter that has become muddy water is put into the treatment tank, so that it covers the grooved drainage drain formed on the bottom of the treatment tank and the open end of this drainage drain. Separation of earth and sand, flock-forming sediments and seawater is possible by the filtered sheet, the waterproof sheet laid on the bottom surface other than the drainage drain, and the sand laminated on the filter sheet and the waterproof sheet. . And by this, seawater can be discharged into the sea area after the turbidity control from the drainage drain through the filter sheet, and the sediment and floc-forming sediment can be discarded after being dehydrated.

  Further, when crushed stone is filled in the drainage drain, impurities contained in seawater can be adsorbed by crushed stone.

  Furthermore, when a water-permeable sand surface coating sheet is provided on the laminated sand, it becomes possible to separate earth and sand from seawater.

  In addition, when a plurality of drainage drains are provided on the bottom surface, dredged dredged sand can be efficiently removed.

  In addition, when the drainage drain is communicated with a storage tank disposed outside the treatment tank, the drainage drain is not saturated with seawater, and continuous seawater filtration is possible.

  In addition, if the filter sheet is made of polyethylene or polyester nonwoven fabric, it is possible to remove minute flocs containing dioxin and tributyltin contained in the separated seawater, and release the sea area after turbidity control. can do.

  In addition, when a drain material is disposed in the treatment tank and a vacuum pump is connected to the drain material, a large amount of sediment with a high water content of sediment in the treatment tank, floc-forming sedimentation deposit, and Dehydrated efficiently.

  According to the seabed sludge removal treatment system of the present invention, the dredged seabed sludge is separated from earth and sand, flock-forming sediments and seawater, and the process up to final disposal of the drowned sludge is efficiently performed, and A large amount of processing can be realized.

It is a plane schematic diagram for demonstrating an example of the removal treatment system of the seabed sludge to which this invention is applied. It is a side surface schematic diagram for demonstrating an example of the removal treatment system of the seabed sludge to which this invention is applied. It is a cross-sectional schematic diagram for demonstrating the drainage drain in the removal processing system of the seabed sludge to which this invention is applied. It is a schematic diagram for demonstrating the effect | action state in the removal treatment system of the seabed sludge to which this invention is applied. It is a side surface schematic diagram for demonstrating the other example of the removal treatment system of the seabed sludge to which this invention is applied. It is a schematic diagram for demonstrating an example of the processing system of the conventional seabed sludge.

Hereinafter, embodiments of the present invention will be described with reference to the drawings to provide an understanding of the present invention.
<Example 1>
FIG. 1 is a schematic plan view for explaining an example of a seabed sludge removal treatment system to which the present invention is applied, and FIG. 2 is a side view for explaining an example of a seabed sludge removal treatment system to which the present invention is applied. FIG.

  The seabed sludge removal treatment system 1 shown here includes a treatment tank 3 in which the seabed sludge is accommodated, a drainage drain 4 disposed on the bottom surface 17 of the treatment tank 3 at regular intervals, and a drainage drain 4 from these drainage drains 4. The guide path 5 that guides drainage and the storage tank 6 that stores drainage from the guide path 5 are configured.

Here, the treatment tank 3 is formed by the surrounding bank 2 having a length of 20 m in length and a height of 70 cm from the ground in consideration of the daily sludge treatment amount (400 m ³ ). The bottom surface 17 is configured to be dug down 60 cm from the ground.

  Further, the drainage drain 4 is arranged on the bottom surface of the treatment tank 3 at regular intervals. As shown in FIG. 3, the drainage drain 4 is configured such that a semicylindrical ridge portion 7 having a diameter of about 300 cm is embedded in the ground 8 and the opening end thereof is flush with the bottom surface 17. Yes.

  Further, the crushed portion 7 is filled with crushed stone 9, and a filter sheet 10 formed of a polyethylene or polyester non-woven fabric is covered on the open end of the heel portion 7. Further, a waterproof sheet 11 made of a vinyl material is covered on the bottom surface 17 other than the area where the filter sheet 10 is covered.

  Here, on the filtration sheet 10 and the waterproof sheet 11, sand 12 for dehydration and filtration having a thickness of about 10 cm is laminated.

  Further, a water-permeable sand surface coating sheet 13 having a conmat of 3 mm is provided on the surface of the sand 12. In addition, on one end side of each flange portion 7, a guide path 5 that is in communication with these flange portions 7 is disposed.

  The guide path 5 extends outside the processing tank 3 while penetrating the lower part of the Go bank 2. In addition, it arrange | positions in the state which the drainage channel 14 faced at the opening end of each guidance path 5. FIG.

  Furthermore, the storage tank 6 is arrange | positioned at the one end side of the drainage channel 14, It is set as the structure which drains the filtrate water stored by this storage tank 6 to the sea etc. with a pump (not shown).

In the seabed sludge removal treatment system of the present invention having the above configuration, first, as shown in FIG. At the same time, the sludge that has been dredged by the dredger device (not shown) is thrown into a removed mud carrier (not shown).
In addition, the depth of sludge is about 10 cm normally.

  Next, the sludge collected in the removed mud transport ship is transported and charged into the treatment tank 3 installed on the land by a sand pump or the like.

  Here, the sludge A introduced into the treatment tank 3 has a very high moisture content, and only the moisture is passed through the sand 12 layer through the sand surface coating sheet 13 coated on the sand 12. Become.

  By passing the sewage through the 12 layers of sand, the sewage is filtered and the floating floc contained in the sewage is removed.

Furthermore, the sewage A filtered by the 12 layers of sand is passed through the filter 7 formed of a polyethylene or polyester nonwoven fabric of the drainage drain 4 into the heel part 7.
In addition, since the waterproof sheet 11 is covered on the bottom surface 17 other than the heel part 7, sewage does not penetrate into the ground, and the water is passed through the drainage drain 4 through the filtration sheet 10 and into the heel part 7.

  Here, the floating floc containing a considerable amount of tributyltin (TBT) can be adsorbed by the filtration sheet 10 and filtered so that the turbidity is less than the regulation value.

Then, the sewage A that has passed through the heel part 7 passes through the guide path 5 and is collected in the storage tank 6.
At this time, the removed seabed sludge contained sulfide (0.1 to 0.2) mg / g, the organic matter contained more than 8% and 10% or less, and DXN was (150 to 1000) pg-TEQ / g-dry. When TBT is (300 to 1000) ng / g, it is discharged after filtering until the turbidity of filtered water is about 2 or less.

  Moreover, when the sulfide contained in the removed seabed sludge is more than 0.3 mg / g, more than 10% organic matter, DXN (1000 to 6000) pg-TEQ / g-dry, TBT more than 1000 ng / g, the turbidity is It discharges, after filtering until it becomes about 0-1 or less.

In addition, dewatered sedimented mud is transported to a dry field and plowed by heavy machinery such as backhoe (transformation of sedimented dewatered mud) to promote atmospheric contact, natural drying, that is, aerobic treatment, and oxidation of sulfides and organic matter. Detoxify.
If there is a lot of organic matter, depending on the weather conditions where the sun drying effect is bad, calcium hypochlorite, quicklime, etc. are sprayed to promote the oxidation of the malodorous compound.

  In the seabed sludge removal treatment system of the present invention, the pre-measurement of harmful substances contained in the treated water is performed, the target value of turbidity is determined based on this measured value, and the sea area is filtered after being set below the set turbidity by multiple nonwoven fabrics. The detoxification process becomes possible by discharging it into the water.

  In addition, the high-water sedimented sludge separated from solid and liquid can be detoxified by aerobic measures after dehydration and volume reduction. It becomes.

  Furthermore, after separating the sediment and floc sediment and seawater, adding sulfide oxidizer and organic oxidizer and mixing them, when there is a lot of organic matter, or under the bad weather drying effect due to bad weather It is possible to promote the oxidation of malodorous compounds by spraying sulfide oxidants such as calcium hypochlorite and lime and organic oxidants.

Note that pg-TEQ / g-dry as a unit representing the environmental concentration of dioxins is “p (pico)”, which is an abbreviation of a prefix representing pico-(= one trillionth). "TEQ" represents a toxic equivalent.
In addition, dioxins are of the same amount (picogram number) and are of the same type (chlorine atom substitution position / number: chlorine atoms can be substituted for hydrogen atoms at all positions except 5 and 10 in the right structural formula) Toxicity varies greatly depending on. Therefore, when evaluating toxicity (effect on the environment), 2, 3, 7, 8-tetrachloro dibenzo-p-dioxin having the right structure, which is the most toxic among dioxins, 2, (3,7,8-dibenzo-baradioxin tetrachloride) is assumed to be 1, and the toxicity intensity of other dioxins is converted and evaluated.

<Example 2>
FIG. 5 is a schematic diagram for explaining an example of a treatment tank in a seabed sludge removal treatment system to which the present invention is applied.

  As shown in detail in FIG. 1, the seabed sludge removal treatment system 1 </ b> A shown here is a treatment tank 3 in which the seabed sludge is stored, and a drainage drain disposed at regular intervals on the bottom surface 17 of the treatment tank 3. 4, a guide path 5 that guides drainage from these drainage drains 4, and a storage tank 6 that stores drainage from the guide path 5.

Here, the treatment tank 3 is formed by the surrounding bank 2 having a length of 20 m in length and a height of 70 cm from the ground in consideration of the daily sludge treatment amount (400 m ³ ). The bottom surface 17 is configured to be dug down 60 cm from the ground.

  Further, the drainage drain 4 is arranged on the bottom surface of the treatment tank 3 at regular intervals. As shown in FIG. 3, the drainage drain 4 has a configuration in which a semicylindrical flange portion 7 having a diameter of about 20 to 30 cm is embedded in the ground 8 and the opening end thereof is flush with the bottom surface 17. Has been.

  The crushed portion 9 is filled with the crushed stone 9, and a filter sheet 10 formed of a polyethylene or polyester nonwoven fabric is covered at the opening end. Further, a waterproof sheet 11 made of a vinyl material is covered on the bottom surface 17 other than the area where the filter sheet 10 is covered.

  Here, a sand 12 for dehydration and filtration having a thickness of about 10 cm is laminated on the filtration sheet 10 and the waterproof sheet 11, and a water-permeable sand surface coating sheet 13 having a conmat of 3 mm is provided on the surface thereof. .

  In addition, on one end side of each ridge portion 7, a guide path 5 communicated with these ridge portions 7 is disposed, and extends outside the treatment tank 3 while penetrating the lower portion of the surrounding dam 2. Has been. In addition, it arrange | positions in the state which the drainage channel 14 faced at the opening end of each guidance path 5. FIG.

  Furthermore, the storage tank 6 is arrange | positioned at the one end side of the drainage channel 14, It is set as the structure which drains the filtrate water stored by this storage tank 6 to the sea etc. with a pump (not shown).

  Here, a drain material 15 is disposed in the treatment tank 3, and a vacuum pump 16 is connected to the drain material 15.

In the seabed sludge removal treatment system of the present invention having the above-described configuration, sludge (also referred to as surface mud, sewage mud, and floating mud) that covers the sea bottom of a fishing port, aquaculture farm, or the like is dredged with seawater (not shown). The sludge that has been dredged is put into a removed mud carrier (not shown).
In addition, the depth of sludge is about 10 cm normally.

  Furthermore, the sludge collected by the removed mud transport ship is transported into the treatment tank 3 installed on the land by a sand pump or the like.

  The sludge A introduced into the treatment tank 3 has a very high water content, and water is sucked by suction of the vacuum pump 16 connected to the drain material 15, so that the sludge A is brought into a compacted state and consolidated. .

  In addition, the sewage in the sludge A passes through the sand 12 layer, so that the sewage is filtered and the floating flock contained in the sewage is removed.

Furthermore, the sewage A filtered by the 12 layers of sand is passed through the filter 7 formed of a polyethylene or polyester nonwoven fabric of the drainage drain 4 into the heel part 7.
In addition, since the waterproof sheet 11 is covered on the bottom surface 17 other than the heel part 7, sewage does not penetrate into the ground, and the water is passed through the drainage drain 4 through the filtration sheet 10 and into the heel part 7.

  Further, the exuded water B that has exuded on the surface of the sludge A and the water sucked from the drain material 15 are stored in a storage tank (not shown). Here, after adjusting the filtration speed, it was confirmed that the turbidity was 2 or less through a multiple non-woven fabric filtration tank (not shown) formed of a polyethylene-based or polyester-based non-woven fabric, and then released into the sea area. To do.

In addition, dewatered sedimented mud is cultivated by heavy machinery such as backhoes (transformation of sedimented mud upside down), promotes air contact and natural drying, measures and stabilizes oxidation of sulfides and organic matter, and then stabilizes it at a general waste treatment plant. At the final geological disposal.
If there is a lot of organic matter, depending on the weather conditions where the sun drying effect is bad, calcium hypochlorite, lime, etc. are sprayed to promote the oxidation of the malodor generating compound.

  In the seabed sludge removal treatment system of the present invention, preliminary prediction measurement after solid-liquid separation of organic substances contained in the removed sediment is performed, and turbidity management that does not affect the sea area is performed and confirmed, and then released into the sea area. Is possible.

  In addition, dehydration of floc sedimentation sediments is carried out by placing drain material on the bottom of the floc sedimentation sediment and performing natural dehydration, thereby dewatering large amounts of sediment with high water content and floc sedimentation sediments efficiently. It becomes possible.

  In addition, the high-moisture sedimented mud that has been separated into solid and liquid is dehydrated and volume-reduced, and then air-dried, making it harmless or stable, so that it can be processed in a relatively secure general waste disposal facility. .

  As a result, in view of the shortage of coastal areas and sediment disposal sites, dehydration, volume reduction, and aerobic induction can be easily performed in parallel to prevent gas generation after geological disposal or outflow of contents. It is possible to reduce the volume of treated mud, facilitate and stabilize the unloading work, and make it harmless.

DESCRIPTION OF SYMBOLS 1, 1A Seabed sludge removal processing system 2 Go embankment 3 Treatment tank 4 Drainage drain 5 Guideway 6 Storage tank 7 Saddle 8 Ground 9 Crushed stone 10 Filtration sheet 11 Waterproof sheet 12 Sand 13 Sand surface coating sheet 14 Drainage path 15 Drain material 16 Vacuum pump 17 Bottom

Claims (7)

A treatment tank into which dredged soil with a high water content containing muddy water is placed;
A grooved drainage drain formed on the bottom surface of the treatment tank;
A filtration sheet coated on the open end of the drainage drain;
A waterproof sheet laid on the bottom surface other than the drainage drain;
A seawater sludge removal treatment system comprising the filtration sheet and sand laminated on the waterproof sheet. The seawater sludge removal treatment system according to claim 1, wherein crushed stone is filled in the drainage drain. The seawater sludge removal treatment system according to claim 1, wherein a water-permeable sand surface coating sheet is provided on the laminated sand. The seawater sludge removal treatment system according to claim 1, wherein a plurality of the drainage drains are provided on the bottom surface. The seawater sludge removal treatment system according to claim 1, 2, 3, or 4, wherein the drainage drain is communicated with a storage tank disposed outside the treatment tank. The seawater sludge removal treatment system according to claim 1, wherein the filtration sheet is formed from a polyethylene-based or polyester-based nonwoven fabric. The drain material is arrange | positioned in the said processing tank, and the vacuum pump was connected to this drain material. The seawater sludge of Claim 1, Claim 2, Claim 3, Claim 5 or Claim 6 Removal processing system.

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